Page 1 of 2 12 LastLast
Results 1 to 25 of 36

Thread: Class D fires

  1. #1
    Join Date
    Feb 2008
    Location
    North of Philly
    Posts
    20,159
    Post Thanks / Like

    Class D fires

    I thought about discussing this in the thread I just posted on dust explosions, but figured it was important enough to discuss on it's own.

    There's probably not a lot of guys here who have ever really thought about class D fires and how to put them out and the dangers involved with them. I bet plenty of us though do both wood and metal working with the same equipment though, so this probably needs to be brought to peoples attention.


    4th reply to the discussion on dust explosions Jerry Frost comments.

    Thermite isn't quite that easy. However something just as dangerous is. A dust comp full of aluminum and wood dust that gets hit by steel sparks makes for a pretty serious fire. Search class D fire.

    Aluminum is not only a useful structural metal but makes for much more effective rocket fuels, incendiary devices, etc. anything that burns can be made hotter with the addition of aluminum from saw dust, shavings or powder. The finer the faster just like most chemical reactions.

    What's even better is how easy it is to light and how HARD it is to put out. Without enough of the right kind of extinguishers burying it in sand is at least a way to keep it from spreading. One of the really nasty things about an aluminum fire is how hot it is and how it will cause other compounds to break down often releasing enough oxy to keep it going. This is why you do NOT put water on a class D, metal, fire. They're hot enough to break water down into hydrogen and oxygen which then burn again only MORE.

    Nasty things Class D fires.
    Here is the link to the original thread over on IFI and the link to my thread here on dust explosions.

    http://www.iforgeiron.com/topic/4629...ning-thermite/

    http://weldingweb.com/vbb/showthread.php...ust-explosions
    .



    No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth!

    Ronald Reagan

  2. #2
    Join Date
    Jan 2011
    Location
    W. Wisc
    Posts
    576
    Post Thanks / Like

    Re: Class D fires

    I thought class D was mostly magnesium fires and that the extinguishers were a "sand" type unit that buried it. ???
    -Dave
    XMT304 with: 22A Feeder, or HF251 Hi Freq DC TIG air cooled

  3. #3
    Join Date
    Feb 2008
    Location
    North of Philly
    Posts
    20,159
    Post Thanks / Like

    Re: Class D fires

    I'm not sure. I know magnesium would be a class D fire, but I don't know all that much about them. I hoped someone with fire training would shed more light on the subject. I know we have more than a few firebugs around here.
    .



    No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth!

    Ronald Reagan

  4. #4
    Join Date
    Jan 2008
    Location
    Lansing, MI
    Posts
    6,117
    Post Thanks / Like

    Re: Class D fires

    Combustible metals are class D fires. Dry powder extinguishing agents are used for them. I had a little fire training when I worked at GM and was on the ERT (basic emergency response team) team for awhile. Put water on a magnesium fire and you best run for your life.

    https://en.m.wikipedia.org/wiki/Fire_class

    We have a local manufacturer who makes car rims and other stuff from magnesium. The place has caught fire a few times and been on the news. Knew a couple guys who worked there and said any water on the floor not in a completely sealed container was grounds for immediate termination. When it comes in contact with burning magnesium it turns into a massive fireball for the most part.

    One of the guys said their belt sanders would get glutted with magnesium swarf from heavy grinding and often catch on fire.

    No place I would ever wanna work!!

    Titanium can catch fire too. We worked with it at Dart but it was all turned on lathes and not ground, where the biggest risk of fire exists being the particles are very fine and can then ignite if exposed to a heat source under the right conditions.
    Last edited by 7A749; 04-16-2016 at 12:52 AM.

  5. #5
    Join Date
    Jan 2004
    Location
    Northern Cal., Shasta County
    Posts
    9,327
    Post Thanks / Like

    Re: Class D fires

    From:https://www.osha.gov/Publications/OSHA_3644.pdf

    "The main precaution in choosing extinguishing
    agents is to use only agents that are compatible
    with the materials present—both those burning
    and those just nearby. For example, using water
    or any water-based agents (such as foam) on any
    burning combustible metals (such as magnesium,
    aluminum, and titanium) can cause an explosible
    reaction....................."

    "The type and quantity of extinguishing agent must
    also be able to extinguish the materials involved
    in a fire. Examples include class C agents for
    live electrical equipment and class D agents for
    combustible metals (see figure 13)."
    "The things that will destroy America are prosperity at any price, peace at any price, safety first instead of duty first, the love of soft living and the get rich quick theory of life." -Theodore Roosevelt

  6. #6
    Join Date
    Oct 2006
    Location
    Illinois
    Posts
    9,654
    Post Thanks / Like

    Re: Class D fires

    Great reminder Doug. You can never be too safe . Even the basic shop work needs to have safety measures on hand and ready.

  7. #7
    Join Date
    Feb 2012
    Posts
    4,228
    Post Thanks / Like

    Re: Class D fires

    No fire training here unless you count starting a few fires.

    For titanium condensate cleanouts; we would remove burning Ti condensate and let burn out and cool on its own on fire brick. We kept a couple 50 gallon drums of salt (NaCl) to suffocate just in case fire bricks didnt keep the mezzanine cool. We suffocated the Ti using hi vac before opening the furnace as much as possible .

    I threw some cold coffee in a garbage can that had less than a shovel full of warm Ti condensate. It started on fire.
    Last edited by Insaneride; 04-16-2016 at 11:45 AM.

  8. #8
    Join Date
    Feb 2008
    Location
    North of Philly
    Posts
    20,159
    Post Thanks / Like

    Re: Class D fires

    Quote Originally Posted by Insaneride View Post
    No fire training here unless you count starting a few fires.
    I have a dive buddy who tells everyone he's a professional arsonist since he gets paid to set things on fire. He works at a burn lab for a place that makes Kidde fire extinguishers and so on and has to do proof tests that batches of things like fire fighting foams work to specs.
    .



    No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth!

    Ronald Reagan

  9. #9
    Join Date
    Jun 2012
    Location
    CT
    Posts
    4,286
    Post Thanks / Like

    Re: Class D fires

    When I was in the fire department we went a long time without class D extinguishers because they are (were?) very spendy. Then we had 4 or 5 VW bugs cash fire and couldn't put out the magnesium engine casing. That's when the town decided to invest in some class D extinguishers. Not long after we got them we used them all up on Kenworth tractor trailer fire. The alloy wheels caught fire and we didn't have enough extinguishers to do the job. After that we only used them if a life was in danger, otherwise, we allowed class D fires to just burn themselves out. But alloy wheels off a TT and VW engine casings are a pretty massive amount of fuel. For a shop, a class D extinguisher might not be a bad idea. https://www.monroeextinguisher.com/p...-extinguisher/

  10. #10
    Join Date
    Jan 2006
    Posts
    1,973
    Post Thanks / Like

    Re: Class D fires

    A bucket of sand works too.

  11. #11
    Join Date
    May 2015
    Location
    Eastern Oregon
    Posts
    254
    Post Thanks / Like

    Re: Class D fires

    I have a question. My Dad is building an Aluminum jet boat, just a small 11 ft, but because he is just learning to weld aluminum he is smoothing down all of his welds with a flapper disc grinder. No steel being down in the shop right now, and I probably wont now until everything is cleaned up. My question is do I have to watch out for anything right now while he is just working on Aluminum only?

  12. #12
    Join Date
    Feb 2008
    Location
    North of Philly
    Posts
    20,159
    Post Thanks / Like

    Re: Class D fires

    Quote Originally Posted by Baloo2327 View Post
    I have a question. My Dad is building an Aluminum jet boat, just a small 11 ft, but because he is just learning to weld aluminum he is smoothing down all of his welds with a flapper disc grinder. No steel being down in the shop right now, and I probably wont now until everything is cleaned up. My question is do I have to watch out for anything right now while he is just working on Aluminum only?
    Not really. Use basic common sense and you all should be fine.
    .



    No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth!

    Ronald Reagan

  13. #13
    Join Date
    Jul 2011
    Location
    Bossier Parish La.
    Posts
    5,824
    Post Thanks / Like

    Re: Class D fires

    Quote Originally Posted by Baloo2327 View Post
    My Dad is building an Aluminum jet boat, just a small 11 ft, but because he is just learning to weld aluminum he is smoothing down all of his welds with a flapper disc grinder.

    Post up a little something about it in the welding projects forum. I would like to see what it looks like.

  14. #14
    Join Date
    Mar 2016
    Location
    North Georgia
    Posts
    1,934
    Post Thanks / Like

    Re: Class D fires

    Was reading this thread and had a similar class d fire once and at the time I knew nothing about putting one out. My fire was an old chain saw. I think it was branded as "David Bradley" and I could be wrong about the name...anyway it was in a building on some property I bought. The saw was in amazing shape and looked like something from the 40s or 50s. I replaced gas line and put modern fuel in, premixed in the can for $18 a quart. Ran saw with no load and had no problem...2 weeks later I was clearing the fence line and my modern stihl fuel tank cracked and started leaking...I got the old big saw out to drop 2 small trees...half way into the first cut it was smelling hot..it seized up and I couldn't pull the rope...tossed it down and then it happened....brightest fire I've seen in person...you could feel the heat or light from 20 ft away. It looked like I giant weld arc about the size of a basket ball...it burned itself out. Only thing left was half of the chain and bar...it made the earth it was sitting on turn to a glass like substance after it was out. I still can't believe they used magnesium for the engine block and cylinder... and what about mag wheels?? If you had a blow out and skidded on a mag what would happen??
    Last edited by Michael ray; 04-17-2016 at 09:10 AM.
    Blue stock- shopmaster, a/bp330, maxstar 150stl, maxstar 210, hf251, Tbolt ac/dc, mm 135
    Red stock-ranger 8, weldanpower 150, idealarc 250 ac/dc
    Esab plasma, Victor OA set, Air products ac/dc 400 amp
    It's me flipped in snow..doughnut fail

  15. #15
    Join Date
    Mar 2016
    Location
    North Georgia
    Posts
    1,934
    Post Thanks / Like

    Re: Class D fires

    I hear of mag welding but that's scary for me...if it's not aluminum or a steel I'm staying away... that's a scary subject
    Blue stock- shopmaster, a/bp330, maxstar 150stl, maxstar 210, hf251, Tbolt ac/dc, mm 135
    Red stock-ranger 8, weldanpower 150, idealarc 250 ac/dc
    Esab plasma, Victor OA set, Air products ac/dc 400 amp
    It's me flipped in snow..doughnut fail

  16. #16
    Join Date
    Mar 2014
    Posts
    4,394
    Post Thanks / Like

    Re: Class D fires

    Quote Originally Posted by Louie1961 View Post
    When I was in the fire department we went a long time without class D extinguishers because they are (were?) very spendy. Then we had 4 or 5 VW bugs cash fire and couldn't put out the magnesium engine casing. That's when the town decided to invest in some class D extinguishers. Not long after we got them we used them all up on Kenworth tractor trailer fire. The alloy wheels caught fire and we didn't have enough extinguishers to do the job. After that we only used them if a life was in danger, otherwise, we allowed class D fires to just burn themselves out. But alloy wheels off a TT and VW engine casings are a pretty massive amount of fuel. For a shop, a class D extinguisher might not be a bad idea. https://www.monroeextinguisher.com/p...-extinguisher/
    Man those are spendy! Don't really understand why since there main component is just sodium chloride. Got to wonder how much of that cost is to cover the manufacturer's liability insurance premiums?

    As an HT I had quite a bit of fire fighting training while in the Navy. All though at this point that training is 35 years in the past so I'm sure there's been some improvements to what's considered "best practice" in different fire fighting situations. As best I can recall our procedure for dealing with Class D fires was "try and get some heavy wood under it and some sand on top of it".

    Reading up on this topic I ended up on the wiki page for "fire extinguishers". It's got some good general info.

    https://en.wikipedia.org/wiki/Fire_extinguisher

  17. #17
    Join Date
    Mar 2016
    Location
    North Georgia
    Posts
    1,934
    Post Thanks / Like

    Re: Class D fires

    I'm going to invest in one of those...even though I don't play with extra dangerous metals. Never know
    Blue stock- shopmaster, a/bp330, maxstar 150stl, maxstar 210, hf251, Tbolt ac/dc, mm 135
    Red stock-ranger 8, weldanpower 150, idealarc 250 ac/dc
    Esab plasma, Victor OA set, Air products ac/dc 400 amp
    It's me flipped in snow..doughnut fail

  18. #18
    Join Date
    Feb 2012
    Posts
    4,228
    Post Thanks / Like

    Re: Class D fires

    Ive had an extinguisher fail on me. I bought it for mandatory requirement when cutting fire wood in the forest. It was about a year old when it failed.

    I was cutting water pipe and sparks started a fire. I knew this would happen so I had a shovel and was saving the extinguisher just in case. My assistant went for the extinguisher and it failed . I was able to put out the fire with shovel and dirt.

    The place I bought it at refilled it. They had a couple lame reasons it failed. 1) they thought it had a metal draw tube that needed replaced with plastic. It was plastic tho. 2) They said its not supposed to be transported or stored horizontally.

    From this failure I learned that its good to slam the bottom into the dirt every now and then to keep the chemicals from clodding up in the draw tube. And, have a backup. Just in case.

    On a side note; Ive heard that HALON makes pigs foam at the mouth and it reduces the atmosphere

  19. #19
    Join Date
    Mar 2014
    Posts
    4,394
    Post Thanks / Like

    Re: Class D fires

    One of my duties aboard ship as an HT was the maintenance and up keep of the ships fire fighting systems and equipment. I think it was every 6 months we had to disassemble our dry (Purple-K) extinguishers and dump them out and inspect them for potential clogging before refilling them. The Purple-K powder is some strange stuff. It's such a fine powder that it sloshes about in a bucket almost just like a liquid does.

  20. #20
    Join Date
    Jan 2010
    Location
    Detroit
    Posts
    741
    Post Thanks / Like

    Re: Class D fires

    Back in the 80's, I used to tig a lot of commercial magnesium bread racks. I would grind out and reweld any cracked welds. Afterward, I'd sweep up all the mag dust, pile it on a welding bench, and light it with an o.a. torch. Yes, I was wearing a 12 shade hood!

  21. #21
    Join Date
    Mar 2016
    Location
    North Georgia
    Posts
    1,934
    Post Thanks / Like

    Re: Class D fires

    #balls
    Blue stock- shopmaster, a/bp330, maxstar 150stl, maxstar 210, hf251, Tbolt ac/dc, mm 135
    Red stock-ranger 8, weldanpower 150, idealarc 250 ac/dc
    Esab plasma, Victor OA set, Air products ac/dc 400 amp
    It's me flipped in snow..doughnut fail

  22. #22
    Join Date
    Mar 2016
    Location
    North Georgia
    Posts
    1,934
    Post Thanks / Like

    Re: Class D fires

    Sounds Iike an electrician wearing a tin foil pair of coveralls and jumping into a 3 phase box...if you know your stuff good enough probably be ok...I'm accident prone
    Blue stock- shopmaster, a/bp330, maxstar 150stl, maxstar 210, hf251, Tbolt ac/dc, mm 135
    Red stock-ranger 8, weldanpower 150, idealarc 250 ac/dc
    Esab plasma, Victor OA set, Air products ac/dc 400 amp
    It's me flipped in snow..doughnut fail

  23. #23
    Join Date
    Jul 2008
    Location
    Long Island
    Posts
    3,006
    Post Thanks / Like

    Re: Class D fires

    Quote Originally Posted by Michael ray View Post
    Was reading this thread and had a similar class d fire once and at the time I knew nothing about putting one out. My fire was an old chain saw...
    Most chainsaw blocks are magnesium. I know that's what Stihl uses too.

  24. #24
    Join Date
    Mar 2016
    Location
    North Georgia
    Posts
    1,934
    Post Thanks / Like

    Re: Class D fires

    I can see the benefits of its weight and strength but after having 1 melt down, that's disturbing at least. I know it's gotta be rare to see that or you'd see them all over the news.
    Blue stock- shopmaster, a/bp330, maxstar 150stl, maxstar 210, hf251, Tbolt ac/dc, mm 135
    Red stock-ranger 8, weldanpower 150, idealarc 250 ac/dc
    Esab plasma, Victor OA set, Air products ac/dc 400 amp
    It's me flipped in snow..doughnut fail

  25. #25
    Join Date
    Feb 2016
    Posts
    17
    Post Thanks / Like

    Re: Class D fires

    http://firefreeze.com/media/Cold%20F...cal%20Book.pdf
    This stuff is pretty amazing. Did a demo at the firehouse and the rep lit a little pile of magnesium , no worries.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Page generated in 1,624,452,255.23769 seconds with 11 queries